Recent advances in the epidemiology, clinical and diagnostic features, and control of canine cardio-pulmonary angiostrongylosis

Abstract

The aim of this review is to provide a comprehensive update on the biology, epidemiology, clinical features, diagnosis, treatment, and prevention of canine cardio-pulmonary angiostrongylosis. This cardiopulmonary disease is caused by infection by the metastrongyloid nematode Angiostrongylus vasorum. The parasite has an indirect life cycle that involves at least two different hosts, gastropod molluscs (intermediate host) and canids (definitive host). A. vasorum represents a common and serious problem for dogs in areas of endemicity, and because of the expansion of its geographical boundaries to many areas where it was absent or uncommon; its global burden is escalating. A. vasorum infection in dogs can result in serious disorders with potentially fatal consequences. Diagnosis in the live patient depends on faecal analysis, PCR or blood testing for parasite antigens or anti-parasite antibodies. Identification of parasites in fluids and tissues is rarely possible except post mortem, while diagnostic imaging and clinical examinations do not lead to a definitive diagnosis. Treatment normally requires the administration of anthelmintic drugs, and sometimes supportive therapy for complications resulting from infection.

Figure 1

Mimicking of adult Angiostrongylus vasorum in situ using reconstructive filming. Note the characteristic barber’s pole appearance of female worms in a still image taken from a filmed sequence of adult live worms, which were collected from naturally infected dogs and placed in a pig’s heart through which fluid was pumped.

Figure 2

SEM photograph of adult Angiostrongylus vasorum . (A) Caudal region, (B) anterior region, (C) a higher magnification of the anterior end showing the oral orifice. Scale bars; A & B = 1 mm; C = 10 μm.

Figure 3

Angiostrongylus vasorum first-stage larva recovered from faeces using the Baermann technique. Note the characteristic kinked tail of the larva with a sinusoidal curve and a spine and distinct notch on the dorsal surface.

Figure 4

Phylogenetic relationships among three species of Angiostrongylus . Neighbor joining analysis was conducted on the concatenated sequences of COI and ITS-2 using the Kimura two-parameter model of nucleotide substitution. Bootstrap values based on 500 replications are given at the internal nodes. Taxa are labeled with the species, strain designation, and country of origin for each isolate.

Figure 5

Photograph showing Angiostrongylus vasorum in situ. Adult male and female A. vasorum (arrow) in the heart of a red fox from the East Midlands region, England.

Figure 6

Radiographic feature of Angiostrongylus vasorum . Latero-lateral thoracic radiograph of an 18 month old English Setter, before treatment for Angiostrongylus vasorum. Diagnosis was confirmed by faecal analysis. Note the marked bronchial-alveolar pattern (arrows).